What are the diagnostic criteria for Hyperosmolar Hyperglycemic State (HHS)?

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From the Guidelines

The diagnostic criteria for Hyperosmolar Hyperglycemic State (HHS) include plasma glucose >600 mg/dL, serum osmolality >320 mOsm/kg, profound dehydration, altered mental status, and minimal or absent ketosis, as stated in the most recent guidelines 1.

Key Diagnostic Criteria

  • Plasma glucose >600 mg/dL (33.3 mmol/L)
  • Serum osmolality >320 mOsm/kg
  • Profound dehydration
  • Altered mental status ranging from confusion to coma
  • Minimal or absent ketosis

Calculation of Effective Serum Osmolality

The effective serum osmolality can be calculated using the formula: 2(Na+) + glucose/18 + BUN/2.8, as mentioned in previous studies 1.

Characterization of HHS

HHS is characterized by severe hyperglycemia without significant ketoacidosis, with arterial pH >7.30 and serum bicarbonate >20 mEq/L, as noted in the guidelines 1.

Clinical Presentation

Patients with HHS usually present with severe dehydration (water deficit of 100-200 mL/kg), hyperosmolality, and pre-renal azotemia with elevated BUN and creatinine, as described in the literature 1.

Mortality Rate

HHS carries a higher mortality rate (10-20%) than diabetic ketoacidosis, primarily affecting elderly patients with type 2 diabetes, as reported in the most recent study 1.

Treatment

Prompt recognition is essential, and treatment requires aggressive fluid resuscitation, insulin therapy, and correction of electrolyte abnormalities, as emphasized in the guidelines 1.

From the Research

Diagnostic Criteria for Hyperosmolar Hyperglycemic State (HHS)

The diagnostic criteria for HHS include:

  • Plasma glucose level >600 mg/dL 2
  • Increased effective plasma osmolality >320 mOsm/kg 2, 3, 4
  • Absence of ketoacidosis 2, 3, 4
  • Marked hypovolaemia 3
  • Hyperglycaemia ≥30 mmol/L 3
  • Osmolality ≥320 mOsm/kg using [(2×Na+) + glucose + urea] 3
  • Without significant ketonaemia (≤3.0 mmol/L) 3
  • Without significant acidosis (pH >7.3) and bicarbonate ≥15 mmol/L 3

Key Differentiators from Diabetic Ketoacidosis (DKA)

The key differentiators for HHS from DKA are:

  • Serum osmolality greater than 320 mOsm/kg 4
  • Lack of metabolic acidosis 4
  • Minimal to no presence of ketones 4

Clinical Features

The clinical features of HHS include:

  • Profound dehydration 5
  • Various neurologic symptoms such as coma 5
  • Disorders of consciousness 6
  • Absent or minimum ketoacidosis 6
  • Severe dehydration (with prerenal hyperazotaemia) 6
  • Plasma hyperosmolarity 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Hyperosmolar Hyperglycemic State.

Emergency medicine clinics of North America, 2023

Research

Hyperosmolar hyperglycemic state.

American family physician, 2005

Research

[Hyperosmolar hyperglycemic state].

Vnitrni lekarstvi, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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